Article pubs.acs.org/IECR
Phase Equilibria and Methane Enrichment of Clathrate Hydrates of Mine Ventilation Air + Tetrabutylphosphonium Bromide Jianwei Du, Huijuan Li, and Liguang Wang* The University of Queensland, School of Chemical Engineering, Brisbane, Queensland 4072, Australia ABSTRACT: This paper reports the experimentally measured phase equilibrium conditions for the clathrate hydrates formed from simulated mine ventilation air (0.50 vol % CH4 + 99.50 vol % air) in the presence of 0, 5, 20, 37.1, and 50 wt % of tetrabutylphosphonium bromide (TBPB). These equilibrium conditions were measured at the temperature range of 281.62− 292.49 K and pressure range of 1.92−18.55 MPa by using an isochoric equilibrium step-heating pressure search method. The results showed that addition of TBPB allowed the hydrate dissociation condition for mine ventilation air to become milder, and at a given temperature, the lowest hydrate dissociation pressure was achieved at 37.1 wt % TBPB, corresponding to the stoichiometric composition for TBPB·32H2O. For each TBPB concentration tested, the semilogarithmic plots of hydrate dissociation pressure versus reciprocal absolute temperature can be satisfactorily fitted to two straight lines intersecting at 6.5 MPa. The slopes of these fitted straight lines are indifferent to changes in TBPB concentration. Gas composition analysis by gas chromatography also found that in the presence of 37.1 wt % TBPB, CH4 could be enriched approximately 3.5-fold in the hydrate phase.
1. INTRODUCTION Fossil fuels will continue to be the primary energy source in the foreseeable future. CO2 generated from fossil fuel combustion needs to be captured and sequestrated. There are many technical options for separation and/or capture of CO2 from combustion flue gas and other industrial effluents.1 However, relatively little attention has been paid to capture of methane, which has an approximately 21 times higher greenhouse effect compared to carbon dioxide. Capture of fugitive methane is attractive environmentally and is a potential energy source.2 One of the major sources of fugitive methane is the dilute methane emitted from coal mine ventilation shafts, known as mine ventilation air (MVA). MVA is most difficult to use as an energy source as the air volume is large and the methane resource is dilute and variable in concentration, generally less than 1.0 vol % methane (typically around 0.3−0.5 vol %).3,4 There is a clear need for enriching methane from low levels up to requirements of lean-burn methane utilization technologies (e.g., 1.0 vol % CH4 for CSIRO system,5 1.6 vol % CH4 for the carburetted gas turbine system,6 and 2.0 vol % CH4 for the Kawasaki turbine system7). The most common attempted methods for capturing methane from MVA include adsorption (solvent adsorption, temperature swing adsorption, pressure swing adsorption) and separation (cryogenic separation and membrane separation).8 These methods are expensive or ineffective for capturing methane from MVA and may suffer from the negative impact of water vapor and particulate contaminations. Gas hydrate crystallization with a lattice of hydrogen bonded water molecules encaging small gaseous molecules such as CO2 or CH4 is a promising method for carbon capture and sequestration.9−11 For MVA, it involves converting methane into hydrate and keeping the other gases in gaseous form, thereby allowing methane to be separated from others. The equilibrium formation pressure of CH4 hydrate is much lower than those of N2 and O2 hydrates at the same temperature.12,13 © 2014 American Chemical Society
Therefore, CH4 enters the hydrate phase preferentially and can be recovered from the CH4−N2−O2 gas mixture after hydrate decomposition.14 Despite its compelling advantages, hydrate formation generally requires high pressure (usually above 5 MPa) at room ambient temperature. A group of additives, known as semiclathrate hydrate (SCH) formers or ionic hydrate formers, can remarkably lower the pressure requirement for hydrate formation.15 A typical SCH former is tetra-n-butyl ammonium bromide (TBAB), which is capable of reducing the hydrate formation pressure and has been extensively investigated for storing and separating gases.11,16−22 TBAB has also been examined for its potential to separate methane from coal methane gas.23,24 However, the methane concentrations in these studies were relatively high, over 25 vol %. Only one theoretical study undertaken by Adamova et al.25 reports the hydrate formation pressure of coal mine gas with dilute methane (0.5 vol % CH4, 75 vol % N2, and 24.5 wt % O2) and suggests that it might be possible to upgrade methane from MVA using gas hydrate technology. Another SCH former tetrabutylphosphonium bromide (TBPB) has recently drawn intention from researchers because of its higher gas storage capacity compared to TBAB and similar capability of reducing hydrate formation pressure.18,26,27 One of the stoichiometric compositions for TBPB hydrate is TBPB·32H2O, which has 10 512 small cages, 16 51262 and four 51263 cages per unit cell.28,29 Recently, the SCH stability conditions of TBPB with pure gases such as CO2,26,30−33 H2,18 CH4,20,26 and N226,32 have been reported, and the experimental conditions are summarized in Table 1. These results show the possibility of capturing CH4 from the MVA at proper Received: Revised: Accepted: Published: 8182
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Table 1. Experimental Conditions for SCHs of Gases + TBPB authors
wt %TBPB
guest gas
T/K
P/MPa
Mayoufi et al.30 Deschamps et al.18 Mayoufi et al.31 Gholinezhad20 Suginaka et al.26 Shi et al.32 Zhang et al.33
37.1 37.1 (5 to 60) 37 35 5, 10, 37.1, 60 10, 20, 35, 50
CO2 H2 CO2 CH4 CO2, CH4, N2 CO2, N2 CO2
281.1−289 285−287.2 284.6−288.5 283.15 282.6−291.6 282.2−292.0 281.0−292.0
0.5−2 12.1−23.3 0.5−1.7 0.1 0.15−5.1 1.32−16.86 0.4−4.0
min. Subsequently, the test solution in the reactor was degassed for 0.5−1 min before undergoing hydrate experiments. The effect of degassing on the concentration of the test solution was negligible. The hydrate dissociation condition measurements were performed at the temperature range of 281.62−292.49 K and pressure range of 1.92−18.55 MPa with using the same isochoric equilibrium step-heating pressure search method as in our previous work.34 Figure 1 shows a typical pressure−
thermodynamic conditions by using gas hydrate technology in the presence of TBPB. To the best of our knowledge, neither experimental measurements of the thermodynamic conditions of TBPB + MVA semiclathrate hydrates nor experimental investigations on the potential viability and efficiency of this separation process have been reported. In the present work, we systematically report the phase equilibrium conditions of MVA + TBPB SCHs and analyze the gas composition in the hydrate whose initial formation pressure is relatively low. These data are essential for technology development for recovering CH4 from MVA by gas hydrate crystallization.
2. EXPERIMENTAL SECTION 2.1. Materials. TBPB (powder, 98 wt % pure) was purchased from Sigma-Aldrich. Simulated ventilation air methane (0.50 vol % CH4 + 99.50 vol % air) was obtained from Coregas. All of these materials were used as received. Deionized water was used to prepare the aqueous solutions of TBPB. 2.2. Experimental Apparatus. The experimental apparatus used for phase equilibrium condition measurements in the present work was the same as in our previous study.34 Briefly, a homemade nonvisual 102 mL stainless steel cylindrical vessel with an inside diameter of 38 mm and inside depth of 90 mm was used as the hydrate reactor. The reactor was immersed in a liquid bath, which was connected to a temperature control circulator (Haake A25). A thermowell coupled with a matched 1/10 DIN ultraprecise immersion RTD sensor (Omega) was inserted into the reactor to measure the liquid or hydrate phase temperature with an uncertainty of ±0.03 K. A pressure transducer (Omega part number MMA5.0KC1P1C2T4A6CE) with accuracy of ±0.01 MPa was used to measure the gas pressure inside the reactor. A magnetically driven stirrer with rotating speed of 600 rpm was used to agitate the test liquid. The gas discharged from a gas booster outlet was fed into the reactor. The experimental data were collected using a data acquisition system (Agilent 34970A) at 10 s intervals. A 362.5 mL stainless steel vessel (model BR300, Berghof) was used to prepare the MVA semiclathrate hydrate samples for gas composition analysis. More details on this vessel can be found in our previous study.36 The gas composition analysis was carried out using a gas chromatograph (GC, Shimazu model GC-2014), which is equipped with Alltech Washed Molesieve 5A 80/100 column, with ultrahigh purity Argon used as carrier gas. 2.3. Experimental Procedures. The hydrate phase equilibrium measurements were carried out as follows. First, the 102 mL high pressure cell was cleaned at least seven times using deionized water and dried prior to introduction of TBPB aqueous solution. The test solution (40 g) was then loaded into the clean and dry reactor. A vacuum pump (Javac CC-45) was used to degas the entire system except the reactor for 5−10
Figure 1. Determination of hydrate dissociation point from a typical pressure−temperature trace.
temperature trace (for 5 wt % TBPB solution + MVA SCH), from which the dissociation point was determined to be 288.51 K and 18.39 MPa. The maximum uncertainties for determining the hydrate dissociation temperatures and pressures were 0.1 K and 0.01 MPa, respectively, which are comparable to the measuring uncertainties reported by Mohammadi and Richon.35 The MVA semiclathrate hydrate samples for gas composition analysis were formed from 75 mL solution in the 362.5 mL vessel with stirring rate of 600 rpm at 278 K and initial pressure 4 MPa. After a sufficiently long period for the hydrate formation to be complete (indicated by gas pressure having remained constant for more than 3 h), the GC was used to measure the gas composition of the coexisting vapor phase in the headspace. Then the vapor phase was completely evacuated from the reactor by using a vacuum pump, followed by dissociation of the hydrate at elevated temperature for releasing the trapped gas, whose composition was measured by the GC. For each gas sample, at least three readings were taken, and their average was recorded. All the gas samples were collected using Tedlar gas sample bags (0.5 L, SKC). Before sampling, the sample bags were degassed by the vacuum pump for 1−2 min and rinsed with the sample gas 3−4 times. 8183
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3. RESULTS AND DISCUSSION The reliability of our experimental system was given in detail in a previous communication of ours,34 which shows excellent agreement between our phase equilibrium data of TBAB + H2O + N2 or CH4 and those reported by other research groups. In the present work, the measured phase equilibrium conditions of MVA SCHs at 0, 5, 20, 37.1, and 50 wt % TBPB are tabulated in Tables 2 and 3 and plotted in Figure 2. For Table 2. Phase Equilibrium Data of MVA Hydrate in the Absence of Chemical Additives simulated ventilation air methane + H2O T/K ± 0.1 276.79 277.22
P/MPa ± 0.01 16.91 17.99
comparison, the phase equilibrium conditions of air hydrate13 are also plotted in Figure 2. As shown, the equilibrium pressure increased with increasing temperature. At a given temperature, the equilibrium pressure of MVA hydrate without chemical additives was lower than that of air hydrate, suggesting that 0.5 vol % CH4 had a stabilizing effect on air hydrate. This result is consistent with the fact that CH4 hydrate is thermodynamically more stable than N2 and O2 hydrates.37 At a given temperature, the equilibrium pressure of MVA hydrate in the absence of any chemical additives was substantially higher than that of MVA + 5 wt % TBPB SCHs. Increasing TBPB concentration from 0 to 20 wt % noticeably shifted the phase equilibrium curve to the lower right region. However, increasing TBPB concentration from 20 to 37.1 wt % shifted the phase equilibrium curve to the right only slightly, and a further increase in TBPB concentration to 50 wt % brought the curve back slightly, indicating that the overly dosed TBPB would have been less effective in reducing the pressure requirement for MVA hydrate formation. Overall, the hydrate equilibrium conditions were less sensitive to changes in TBPB concentration in the range of 20−50 wt % than those in the range of 0−20 wt %, and the most thermodynamically stable equilibrium condition was obtained at 37.1 wt % TBPB. Similar observation was made by other workers for the hydrate phase equilibrium conditions of N2 + TBPB solution.32 When reporting the hydrate phase equilibrium data of a gas mixture, one should consider reporting the composition of the gas in the headspace of the reactor under hydrate equilibrium condition.38,39 In this work, the phase equilibrium data were reported with the assumption that the composition of the simulated MVA sourced from the gas cylinder was the same as that in the reactor under hydrate dissociation conditions because there was a large volume of gas in the headspace of the
Figure 2. Phase equilibrium data of MVA in the presence of TBPB at different concentrations: ○, deionized water (0 wt %); ■, 5 wt %; ▲, 20 wt %; ●, 37.1 wt %; ×, 50 wt %. ◇, air + deionized water (adapted from ref 13). The lines are drawn to guide the eye.
reactor, and the solubility of CH4 and air in water would be exceedingly low and close to each other. Final proof for this assumption would require measurements of the solubility of CH4 and air in TBPB solutions. Comparison of hydrate dissociation conditions in TBPB + MVA, CH4 or N2 systems was made and is presented in Figure 3 by the semilogarithmic plot of semiclathrate hydrate phase equilibrium pressure (lnP) versus reciprocal temperature (1/ T). As a first approximation, these SCH systems can be considered roughly complying with the requirement of the Clausius−Clapeyron equation, and the energetics of SCH dissociation can be inferred by the slope of the straight lines fitted to lnP versus 1/T data. The equilibrium data reported in ref 33 for N2 + TBPB SCHs (above 7 MPa) can be satisfactorily fitted to straight lines with the same slope, irrespective of TBPB concentration (see Figure 3a), suggesting that the concentration of TBPB has little influence on the enthalpy of hydrate dissociation. The lnP versus 1/T plots made from the equilibrium data (below 5 MPa) adapted from ref 26 can be satisfactorily fitted by two straight lines intersecting at 1.8 MPa for the N2 + 35 wt % TBPB SCH and 0.8 MPa for the CH4 + 35 wt % TBPB SCH. Likewise, the equilibrium data for MVA + TBPB SCHs obtained in the present work can be satisfactorily fitted to two straight lines crossing over each other at 6.5 MPa, at all TBPB concentrations tested. Overall, the heat of dissociation seemed smaller at higher pressures, which could be attributed to an occupation change of guest gas molecules in the empty cages of these SCHs. According to Sloan and Koh,37 the approximate heat of
Table 3. Phase Equilibrium Data of MVA in the Presence of TBPB at Different Concentrations MVA + TBPB + H2O 5 wt %
20 wt %
37.1 wt %
50 wt %
T/K ± 0.1
P/MPa ± 0.01
T/K ± 0.1
P/MPa ± 0.01
T/K ± 0.1
P/MPa ± 0.01
T/K ± 0.1
P/MPa ± 0.01
281.62 282.99 285.13 286.96 288.51
1.92 4.62 9.31 14.18 18.39
285.05 285.85 288.18 290.35 292.02
2.52 3.81 8.14 13.77 18.55
285.26 287.45 289.68 291.41 292.49
1.99 5.57 9.96 14.48 18.33
285.3 286.77 288.41 290.49 292.22
2.57 5.08 8.11 12.87 18.12
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Figure 3. Semilogarithmic plot of semiclathrate hydrate phase equilibrium pressure versus reciprocal phase equilibrium temperature: (a) pure gases; (b) MVA.
contained in the air enter these cages.45 Pure nitrogen and oxygen also form structure II hydrates, whereas pure methane forms structure I hydrate, which is built from six large and two small cages per unit cell.17 It is reported that TBAB semiclathrate hydrate can only incorporate gas molecules that fit in the empty small cage.46 It is, therefore, possible that MVA semiclathrate hydrates formed from TBPB solutions might also incorporate the gases in the small cages alone. Further work with applying suitable techniques such as Raman spectroscopy is needed to understand the cage filling. The observed enrichment of CH4 and O2 in the MVA semiclathrate hydrate phase could be attributed to the higher affinity of CH4 and O2 to the small cages compared to that of N2. At 273.15 K, for ordinary gas hydrates, the dissociation pressures of CH4 and O2 hydrates are almost 13 and 4 MPa lower than that of N2 hydrate, respectively.26,37 Likewise, at a given temperature and TBPB concentration, the dissociation pressure of CH4 + TBPB semiclathrate hydrate is much lower than that of N2 + TBPB semiclathrate hydrate.26,32
dissociation should be relevant to cavity occupation, and less energy is required to dissociate structures with more cavities filled than those with fewer cavities filled. The above slope change might also be linked to a possible hydrate structure transition induced by the pressure change, which points to the need for further work with applying suitable techniques such as Raman spectroscopy or X-ray to examine the hydrate structure at different pressures. To verify the potential viability of the hydrate-based separation method for methane capture from MVA with TBPB, we measured the gas composition (CH4, N2, and O2 content, on a water-free basis) of the hydrate phase formed from 75 mL of 37.1 wt % TBPB solution at 278 K (subcooling was 8.5 K) and initial pressure 4 MPa. The experiment was repeated independently. Table 4 shows that the hydrate phase Table 4. Composition of Gases (on a Water-Free Basis) in Different Phasesa hydrate phase coexisting gas phase
CH4 (vol %)
N2 (vol %)
O2 (vol %)
1.75 ± 0.05 0.45 ± 0.05
72.4 ± 0.3 79.4 ± 1.4
25.5 ± 0.2 19.9 ± 0.8
4. CONCLUSIONS The phase equilibrium conditions of SCHs formed from mine ventilation air in the presence of at 0, 5, 20, 37.1, and 50 wt % TBPB were measured in the temperature range of 281.62− 292.49 K and pressure range of 1.92−18.55 MPa. It was found that addition of TBPB moved the MVA hydrate equilibrium conditions to higher temperatures and lower pressures, and the most thermodynamically stable TBPB + MVA SCH was obtained at 37.1 wt %. The hydrate equilibrium conditions were relatively indifferent to changes in TBPB concentration from 20 to 50 wt %. For each TBPB concentration tested, the semilogarithmic plots of hydrate dissociation pressure versus reciprocal absolute temperature can be satisfactorily fitted to two straight lines crossing over each other at 6.5 MPa. The slopes of these fitted straight lines are indifferent to changes in TBPB concentration. It was also found that in the presence of 37.1 wt % TBPB, CH4 was preferentially incorporated into the hydrate phase, and the enrichment was approximately 3.5-fold, suggesting that a hydrate-based method is promising for separating methane from MVA.
a
Feed gas composition = 0.50 vol % CH4 + 78.6 vol % N2 + 20.9 vol % O2.
had an average CH4 content of 1.75 vol %, with standard deviation of 0.05 vol %. This CH4 content was 3.5 times higher than that of the feed gas (i.e., 0.50 vol %), suggesting that CH4 was substantially enriched in the hydrate phase and that it is promising to separate methane from MVA by clathrate hydrate crystallization aided by TBPB. Further work is underway to improve the selectivity and efficiency of this process and the results will be reported in the next communication. Note that the O2 content in the MVA semiclathrate hydrate phase was also higher than in the feed gas, in contrast to the decreased N2 content. This finding is coincident with the reported substantial oxygen enrichment in the natural air hydrate formed in Arctic and Antarctic ice sheets40,41 and synthetic air hydrate42,43 probably owing to the preferential occupation of small cavities by O2 in air hydrate.44 Air hydrates usually form a type II crystal structure, which is built from 8 large and 16 small cages per unit cell, and nitrogen and oxygen 8185
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butyl ammonium bromide semi-clathrate hydrate. Jpn. J. Appl. Phys. Part 1 2004, 43 (1), 362−365. (18) Deschamps, J.; Dalmazzone, D. Hydrogen Storage in Semiclathrate Hydrates of Tetrabutyl Ammonium Chloride and Tetrabutyl Phosphonium Bromide. J. Chem. Eng. Data 2010, 55 (9), 3395−3399. (19) Sizikov, A. A.; Manakov, A. Y.; Rodionova, T. V. Methane Capacity of Double Tetrabutylammonium Bromide plus Methane Ionic Clathrate Hydrates. Energy Fuels 2012, 26 (6), 3711−3716. (20) Gholinezhad, J. Experimental Investigation of Semi-Clathrate Hydrates with Application Towards Gas Storage, Transportation and Separation. PhD thesis, Heriot-Watt University, 2012. (21) Ricaurte, M.; Dicharry, C.; Broseta, D.; Renaud, X.; Torre, J. P. CO2 Removal from a CO2-CH4 Gas Mixture by Clathrate Hydrate Formation Using THF and SDS as Water-Soluble Hydrate Promoters. Ind. Eng. Chem. Res. 2013, 52 (2), 899−910. (22) Zhong, D.-l.; Ye, Y.; Yang, C.; Bian, Y.; Ding, K. Experimental Investigation of Methane Separation from Low-Concentration Coal Mine Gas (CH4/N2/O2) by Tetra-n-butyl Ammonium Bromide Semiclathrate Hydrate Crystallization. Ind. Eng. Chem. Res. 2012, 51 (45), 14806−14813. (23) Sun, Q.; Guo, X.; Liu, A.; Liu, B.; Huo, Y.; Chen, G. Experimental study on the separation of CH4 and N2 via hydrate formation in TBAB solution. Ind. Eng. Chem. Res. 2011, 50 (4), 2284− 2288. (24) Zhong, D.-L.; Ye, Y.; Yang, C. Equilibrium Conditions for Semiclathrate Hydrates Formed in the CH4 + N2 + O2 + Tetra-n-butyl Ammonium Bromide Systems. J. Chem. Eng. Data 2011, 56 (6), 2899−2903. (25) Adamova, T. P.; Subbotin, O. S.; Chen, L. J.; Belosludov, V. R. Theoretical investigation of the possibility of using multicomponent (N2-O2-CH4-H2O) clathrate hydrates for methane recovery from mine gas. J. Eng. Thermophys. 2013, 22 (1), 62−68. (26) Suginaka, T.; Sakamoto, H.; Iino, K.; Sakakibara, Y.; Ohmura, R. Phase equilibrium for ionic semiclathrate hydrate formed with CO2, CH4, or N2 plus tetrabutylphosphonium bromide. Fluid Phase Equilib. 2013, 344 (0), 108−111. (27) Mohammadi, A. H.; Eslamimanesh, A.; Belandria, V.; Richon, D. Phase equilibria of semiclathrate hydrates of CO2, N2, CH4, or H2 + Tetra-n-butylammonium bromide aqueous solution. J. Chem. Eng. Data 2011, 56 (10), 3855−3865. (28) Dyadin, Y. A.; Udachin, K. A. Clathrate Polyhydrates of Peralkylonium Salts and Their Analogs. J. Struct. Chem. 1987, 28 (3), 394−432. (29) Dyadin, Y. A.; Udachin, K. A. Clathrate formation in waterperalkylonium salts systems. J. Inclusion Phenom. 1984, 2 (1−2), 61− 72. (30) Mayoufi, N.; Dalmazzone, D.; Fürst, W.; Delahaye, A.; Fournaison, L. CO2 Enclathration in Hydrates of Peralkyl(Ammonium/Phosphonium) Salts: Stability Conditions and Dissociation Enthalpies. J. Chem. Eng. Data 2009, 55 (3), 1271−1275. (31) Mayoufi, N.; Dalmazzone, D.; Delahaye, A.; Clain, P.; Fournaison, L.; Fürst, W. Experimental Data on Phase Behavior of Simple Tetrabutylphosphonium Bromide (TBPB) and Mixed CO2 + TBPB Semiclathrate Hydrates. J. Chem. Eng. Data 2011, 56 (6), 2987−2993. (32) Shi, L.-L.; Liang, D.-Q.; Li, D.-L. Phase Equilibrium Data of Tetrabutylphosphonium Bromide Plus Carbon Dioxide or Nitrogen Semiclathrate Hydrates. J. Chem. Eng. Data 2013, 58 (7), 2125−2130. (33) Zhang, P.; Ye, N.; Zhu, H.; Xiao, X. Hydrate Equilibrium Conditions of Tetra-n-butylphosphonium Bromide + Carbon Dioxide and the Crystal Morphologies. J. Chem. Eng. Data 2013, 58 (6), 1781− 1786. (34) Du, J.; Wang, L. Equilibrium Conditions for Semi-Clathrate Hydrates Formed with CO2, N2 or CH4 in the Presence of Tri-nbutylphosphine Oxide. Ind. Eng. Chem. Res. 2014, 53 (3), 1234−1241. (35) Mohammadi, A. H.; Richon, D. Phase equilibria of hydrogen sulphide clathrate hydrates in the presence of single or mixed salt aqueous solution. J. Chem. Thermodyn. 2012, 53 (0), 82−85.
AUTHOR INFORMATION
Corresponding Author
*Tel: +61-7-33657942; e-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors gratefully appreciate the financial support from Australian Research Council under the Discovery Projects scheme (No. 1092846) and thank Prof. Joe da Costa, Dr. Simon Smart, and Dr. Julius Motuzas for their help with the gas composition analysis.
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REFERENCES
(1) Yang, H.; Xu, Z.; Fan, M.; Gupta, R.; Slimane, R. B.; Bland, A. E.; Wright, I. Progress in carbon dioxide separation and capture: A review. J. Environ. Sci. 2008, 20 (1), 14−27. (2) Bibler, C. J.; Marshall, J. S.; Pilcher, R. C. Status of worldwide coal mine methane emissions and use. Int. J. Coal Geol. 1998, 35 (1), 283−310. (3) Noack, K. Control of gas emissions in underground coal mines. Int. J. Coal Geol. 1998, 35 (1−4), 57−82. (4) Karakurt, I.; Aydin, G.; Aydiner, K. Mine ventilation air methane as a sustainable energy source. Renewable Sustainable Energy Rev. 2011, 15 (2), 1042−1049. (5) Su, S.; Agnew, J. Catalytic combustion of coal mine ventilation air methane. Fuel 2006, 85 (9), 1201−1210. (6) Carothers, F. P.; Schultz, H. L.; Talkington, C. C. Mitigation of Methane Emissions from Coal Mine Ventilation Air: an Update; U.S. Environmental Protection Agency: Washington, DC, 2003. (7) Tanaka, K.; Yoshino, Y.; Kashihara, H.; Kajita, S. Utilization and Mitigation of VAM/CMM Emissions by a Catalytic Combustion Gas Turbine. In Cleaner Combustion and Sustainable World; Qi, H.; Zhao, B., Eds.; Springer: Berlin Heidelberg, 2013; pp 401−406. (8) Su, S.; Beath, A.; Guo, H.; Mallett, C. An assessment of mine methane mitigation and utilisation technologies. Prog. Energy Combust. Sci. 2005, 31 (2), 123−170. (9) Giavarini, C.; Maccioni, F.; Politi, M.; Santarelli, M. L. CO2 Hydrate: Formation and Dissociation Compared to Methane Hydrate. Energy Fuels 2007, 21 (6), 3284−3291. (10) Kiyono, F.; Yamazaki, A.; Ogasawara, K. In Cost Estimation of CO2 Recovery Technology Using Hydrates, Preprints of Symposia, American Chemical Society, Division of Fuel Chemistry; Washington, DC, 2002, 77−78. (11) Duc, N. H.; Chauvy, F.; Herri, J.-M. CO2 capture by hydrate crystallization - A potential solution for gas emission of steelmaking industry. Energy Convers. Manage. 2007, 48 (4), 1313−1322. (12) Servio, P.; Englezos, P. Measurement of Dissolved Methane in Water in Equilibrium with Its Hydrate. J. Chem. Eng. Data 2001, 47 (1), 87−90. (13) Mohammadi, A. H.; Tohidi, B.; Burgass, R. W. Equilibrium Data and Thermodynamic Modeling of Nitrogen, Oxygen, and Air Clathrate Hydrates. J. Chem. Eng. Data 2003, 48 (3), 612−616. (14) Eslamimanesh, A.; Mohammadi, A. H.; Richon, D.; Naidoo, P.; Ramjugernath, D. Application of gas hydrate formation in separation processes: A review of experimental studies. J. Chem. Thermodyn. 2012, 46, 62−71. (15) Arjmandi, M.; Chapoy, A.; Tohidi, B. Equilibrium data of hydrogen, methane, nitrogen, carbon dioxide, and natural gas in semiclathrate hydrates of tetrabutyl ammonium bromide. J. Chem. Eng. Data 2007, 52 (6), 2153−2158. (16) Shimada, W.; Ebinuma, T.; Oyama, H.; Kamata, Y.; Takeya, S.; Uchida, T.; Nagao, J.; Narita, H. Separation of gas molecule using tetra-n-butyl ammonium bromide semi-clathrate hydrate crystals. Jpn. J. Appl. Phys. Part 2 2003, 42 (2A), L129−L131. (17) Kamata, Y.; Oyama, H.; Shimada, W.; Ebinuma, T.; Takeya, S.; Uchida, T.; Nagao, J.; Narita, H. Gas separation method using tetra-n8186
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(36) Du, J.; Li, H.; Wang, L. Formation Kinetics of Methane Hydrate in the Presence of Ionic Surfactants; Chemeca 2013: Australasian Conference on Chemical Engineering, Brisbane, Australia, 2013. (37) Sloan, E. D.; Koh, C. A. Clathrate Hydrates of Natural Gases, 3rd ed.; CRC Press, Taylor & Francis: New York, 2008. (38) Beltran, J. G.; Bruusgaard, H.; Servio, P. Gas hydrate phase equilibria measurement techniques and phase rule considerations. J. Chem. Thermodyn. 2012, 44 (1), 1−4. (39) Kumar, R.; Wu, H.-j.; Englezos, P. Incipient hydrate phase equilibrium for gas mixtures containing hydrogen, carbon dioxide and propane. Fluid Phase Equilib. 2006, 244 (2), 167−171. (40) Nakahara, J.; Shigesato, Y.; Higashi, A.; Hondoh, T.; Langway, C. C., Jr. Raman spectra of natural clathrates in deep ice cores. Philos. Mag. B 1988, 57 (3), 421−430. (41) Ikeda, T.; Fukazawa, H.; Mae, S.; Pepin, L.; Duval, P.; Champagnon, B.; Lipenkov, V.; Hondoh, T. Extreme fractionation of gases caused by formation of clathrate hydrates in Vostok Antarctic ice. Geophys. Res. Lett. 1999, 26 (1), 91−4. (42) Liu, C. L.; Ye, Y. G.; Lu, H. L.; et al. Formation and Raman spectroscopic characteristics of nitrogen, oxygen and air hydrates. Geoscience 2008, 22 (3), 480−4. (43) Kuhs, W. F.; Klapproth, A.; Chazallon, B. Chemical physics of air clathrate hydrates. Phys. Ice Core Rec. 2000, 373−392. (44) Ohno, H.; Hondoh, T., Edited by Kuhs, W. F.Physics and Chemistry of Ice: Proceedings of the International Conference on the Physics and Chemistry of Ice, 11th, Royal Society of Chemistry, Cambridge, UK, 2007; pp 459−467. (45) Hondoh, T.; Anzai, H.; Goto, A.; Mae, S.; Higashi, A.; Langway, C. C., Jr. The crystallographic structure of the natural air-hydrate in Greenland dye-3 deep ice core. J. Inclusion Phenom. Mol. Recognit. Chem. 1990, 8 (1−2), 17−24. (46) Kamata, Y.; Oyama, H.; Shimada, W.; Ebinuma, T.; Takeya, S.; Uchida, T.; Nagao, J.; Narita, H. Gas separation method using tetra-nbutyl ammonium bromide semi-clathrate hydrate. Jpn. J. Appl. Phys. 2004, 43 (1), 362−365.
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dx.doi.org/10.1021/ie5000664 | Ind. Eng. Chem. Res. 2014, 53, 8182−8187
